In general, inkjet printing machines or printers include at least one printhead that ejects drops or jets of liquid ink onto a recording or image forming surface. An aqueous inkjet printer employs water-based or solvent-based inks in which pigments or other colorants are suspended or in solution. Once the aqueous ink is ejected onto an image receiving surface by a printhead, the water or solvent is evaporated to stabilize the ink image on the image receiving surface. When aqueous ink is ejected directly onto media, the aqueous ink tends to soak into the media when it is porous, such as paper, and change the physical properties of the media. To address this issue, indirect printers have been developed that eject a skin layer onto the blanket mounted to a drum or endless belt, and an ink layer onto the skin layer. The ink is dried on the skin layer and then transferred to media. Such a printer avoids the changes in media properties that occur in response to media contact with the water or solvents in aqueous ink. Indirect printers also reduce the effect of variations in other media properties that arise from the use of widely disparate types of paper and films used to hold the final ink images.
In these indirect printers, media stripping may be a problem. Both the skin and the ink layer must adhere to the media so that the image is transferred to the media. However, high adhesion also makes stripping the media and ink image from the blanket difficult, particularly when relatively thin media are used. Air knives have been proposed to aid in media stripping in the past. Insufficient media lead edge separation from the blanket usually prevents an air knife from successfully stripping the media from the blanket. Stripper fingers have also been proposed for this purpose, but they must be pressed into the blanket with high pressures in order to strip the lead edge of the media from the blanket. Such high pressures increase the wear and reduce the life of the blanket. Other ways of successfully stripping media from a blanket in an inkjet printer without adversely affecting the blanket surface would be beneficial.